The Communist Party of Australia (CPA) was founded in 1920 and dissolved in 1991. The CPA achieved its greatest political strength in the 1940s and faced an attempted ban in 1951. Though it never presented a major challenge to the established order in Australia, it did have significant influence on the trade unions, social movements, and the national culture.

The Communist Party of Australia was founded in Sydney in October 1920 by a group of socialists inspired by reports of the Russian Revolution. Among the party's founders were a prominent Sydney trade unionist, Jock Garden, Adela Pankhurst (daughter of the British suffragist Emmeline Pankhurst), Tom Walsh, and most of the then illegal Australian section of the Industrial Workers of the World (IWW). The IWW soon left the Communist Party, with its original members, over disagreements with the direction of the Soviet Union and Bolshevism. In its early years, mainly through Garden's efforts, the party achieved some influence in the trade union movement in New South Wales, but by the mid-1920s it had dwindled to an insignificant sect. Garden and other communists were expelled from the Labor Party in 1924. The CPA ran candidates including Garden at the 1925 NSW state election in working-class seats against the ALP, but was decisively defeated, and prompting Garden to leave the party in 1926 and returned to the Labor Party.

The leadership of the party went to Jack Kavanagh, an experienced Canadian communist activist who had moved to Australia in 1925, and Esmonde Higgins, a talented Melbourne journalist who was the nephew of a High Court judge, H.B. Higgins. But in 1929 the party leadership fell into disfavour with the Comintern, which under orders from Joseph Stalin had taken a turn to extreme revolutionary rhetoric (the so-called "Third Period"), and an emissary, the American Communist Harry Wicks, was sent to correct the party's perceived errors. Kavanagh was expelled in 1930 and Higgins resigned.

The Communist Party began to win positions in trade unions such as the Miners Federation and the Waterside Workers Federation, although its parliamentary candidates nearly always polled poorly at elections.

In 1939 Nazi Germany and Stalin's Soviet Union signed a Non-Aggression Treaty and, despite foundational antipathies between the dictatorships, and after failed diplomatic attempts at preventing Nazi aggression vis-a-vis the West, the USSR agreed not to engage in hostilities against Germany at the outbreak of World War II (Australia declared war on Nazi Germany for invading Poland). A secret protocol of the Non-Aggression Treaty stipulated that the USSR may invade and annex East Poland. Consequently the Communist Party of Australia opposed and sought to disrupt Australia's "imperialist" war effort against Nazism in the early stages of the War under orders of the Commintern, which sought to buy time for the USSR to increase its military capability in the context of an expected Nazi invasion. Menzies banned the CPA after the fall of France in 1940, but by 1941 Stalin was forced to join the allied cause when Hitler reneged on the Pact and invaded the USSR. The USSR came to bear the brunt of the carnage of Hitler's war machine and the Communist Party in Australia lost its early war stigma as a result.[1] Its membership rose to 20,000, it won control of a number of important trade unions, and a Communist candidate, Fred Paterson, was elected to the Queensland parliament. But the party remained marginal to the Australian political mainstream. The Australian Labor Party remained the dominant party of the Australian working class.

After 1945 and the onset of the Cold War, the party entered a steady decline. Following the new line from Moscow, and believing that a new "imperialist war" and a new depression were imminent, and that the CPA should immediately contest for leadership of the working class with the Australian Labor Party, the CPA launched an industrial offensive in 1947, culminating in a prolonged strike in the coalmines in 1949. The Chifley Labor government saw this as a communist challenge to its position in the labour movement, and used the army and strikebreakers to break the strike. The Communist Party never again held such a strong position in the union movement.

By the 1960s the party's membership had fallen to around 5,000,[4] but it continued to hold positions in a number of trade unions, and it was also influential in the various protest movements of the period, especially the movement against the Vietnam War. In 1966, the party started their own magazine called Australian Left Review. But the Soviet invasion of Czechoslovakia in 1968 triggered another crisis. Sharkey's successor as party leader, Laurie Aarons, denounced the invasion, and a group of pro-Soviet hardliners left in 1971 to form a new party, the Socialist Party of Australia.

Through the 1970s and 1980s the party continued to decline, despite adopting Eurocommunism and democratising its internal structures so that it became a looser radical party rather than a classic Marxist-Leninist one. By 1990 its membership had declined to less than a thousand.

In 1991, the Communist Party was dissolved and the New Left Party formed. The New Left Party was intended to be a broader party which would attract a wider range of members, which did not happen, and the New Left Party disbanded in 1992. The assets of the Communist Party were thereafter directed into the SEARCH Foundation,[5] a not-for-profit company set up in 1990 "to preserve and draw on the resources of the Communist Party of Australia and its archives."[6] The archives of the party are now held at the State Library of NSW[7] and can be accessed with the written permission of the SEARCH Foundation.

In 1996, the Socialist Party took up the now-unused name of Communist Party of Australia (see Communist Party of Australia (current)). This party, along with a number of small Trotskyist groups, maintains the communist tradition in Australia, but none of these groups is of any political significance.

Despite its peripheral role in Australian politics and its ultimate failure, the Communist Party had an influence far beyond its numbers. From 1935 to the 1960s it occupied leadership positions in a number of important trade unions, and was at centre of many major industrial conflicts. Many of its members played leading roles in Australian cultural life, such as the novelists Katharine Susannah Prichard, Judah Waten, Frank Hardy, Eric Lambert and Alan Marshall, the painter Noel Counihan and the poet David Martin.

In some ways, the negative reactions to the Communist Party were more important than anything the party itself did. Conservative politicians such as Stanley Bruce in the 1920s and Robert Menzies in the 1950s won elections partly by linking the Australian Labor Party with communism. In the early 1950s Catholics in the Labor Party were led by anti-communism to form "Industrial Groups" to combat communist influence in the unions. This led to the Australian Labor Party split of 1955 and the formation of the Democratic Labor Party, which used its power to influence voters' preferences at elections to keep the ALP out of power.

The Communist Party and its members campaigned for many years for causes such as improved conditions for industrial workers, opposition to fascist and other dictatorships, equal rights for women and civil rights for the Aboriginal people. It achieved some successes in these areas, and many of its positions were later taken up by the political mainstream. But the party never succeeded in garnering significant support for communism. The party was an apologist for the Soviet Union for many years (although it became critical of the Soviet Union from the late 1960s). Disenchantment with the Soviet Union was a leading cause of the loss of membership.

The youth wing of CPA worked under several different names in different periods, such as Young Communists, Eureka Youth League, Young Socialist League and Young Communist Movement of Australia. The Eureka Youth League was a founding member of the World Federation of Democratic Youth, a membership later taken over by the Young Communist Movement.